The Black Cats have remained in contact with Liverpool regarding the Italian, despite the striker having turned down a €18 million move to the Stadium of Light earlier in July
Sunderland are hopeful of resurrecting a deal to sign Liverpool striker Fabio Borini this summer.
The Wearside club had agreed an €18 million transfer fee to sign the Italian permanently after spending last season on loan at the Stadium of Light.
But Borini rejected the move in favour of fighting for a first-team place at Anfield next season, though that hasn't stopped Sunderland maintaining hope of sealing a deal.
However, a shoulder injury sustained by Borini in pre-season action with Liverpool has seen talks stall.
"He is being assessed now for his shoulder injury," Sunderland boss Gus Poyet said during a pre-season training camp in Portugal. "That's stopped everything a little bit.
"We will see. I have not held talks with him, but the club has, although that's private. We know where we stand."
Poyet is growing increasingly frustrated at Sunderland's failure to push through deals this summer, with sporting director Lee Congerton not approving a move for Atletico Madrid's Cristian Rodriguez.
The Black Cats boss is keen to bring in four more players to add to the signings of Patrick van Aanholt, Jordi Gomez, Billy Jones and Costel Pantilimon.
"One or two they are close, but if you had asked me last week I would have said those two were close too," said Poyet.
"I cannot wait another week. We are going to be off Monday and Tuesday, so next Wednesday I need to have four new players.
"It's clear we need a few new players, and it has not been as quick as I would have expected. It's getting a little close to the part where I really want to work with the main squad.
"I am like any other manager, the sooner you get the players the better. I hope it is now, today, tomorrow.
"The finances of the transfer, the finances of the player, that’s the part where I don’t get involved. I like to plan, and it has been very difficult."